On July 21, 1969, after landing in the Moon’s Sea of Tranquility, Apollo 11 astronauts Neil Armstrong and Buzz Aldrin planted an American flag and spent almost three hours exploring the lunar terrain. The Moon’s airless, inert surface should preserve their footprints and equipment for millions of years. But new robotic rovers due to begin visiting the Moon next summer threaten to radically accelerate the site’s decay, prompting preservationists to ask how best to protect off-world archaeological sites as the heritage of future generations.

The impetus behind the robotic voyage is the Google Lunar X Prize, which could pay $20 million or more to the first team to successfully land a rover on the Moon and accomplish a set list of tasks. Fourteen teams from around the world have registered, but only one, Astrobotic Technology, has publicly announced its planned itinerary: a trip to the Apollo 11 site next summer, shortly after the first mission’s 40th anniversary. Astrobotic Tech representative David Gump says their rover will land far from the Apollo 11 site and will be able to recognize and circumvent footprints and artifacts on the lunar surface, but not everyone shares this op-timism. John Logsdon, director of George Washington University’s Space Policy Institute, believes the team should first perform trial runs on Earth.

“I’d like to see them demonstrate their ability to do a precision landing someplace else before they try it next to the Apollo 11 site,” Logsdon says. “You wouldn’t have to be very far off to come down on top of the flag or something dramatic like that.” Precision landings are further complicated by the fact that most sites are known to accuracies of only, at best, tens of meters. New Mexico State University anthropologist Beth O’Leary proposes that NASA’s Lunar Reconnaissance Orbiter, launching this October, be used to survey these sites before any landings are attempted.

Since 1999 O’Leary has headed the Lunar Legacy Project, an effort to protect the Apollo 11 landing site as either a US National Historic Landmark or a UNESCO World Heritage Site. But so far neither the US National Park Service nor the United Nations has moved to extend its purview beyond Earth. The Federal Aviation Administration (FAA) could effectively protect the site from incursions by refusing to issue a launch license for missions that might disturb it. But the FAA can’t control teams launching from non-US spaceports, and American rovers will certainly not be the last to return to a historic place on the Moon.

Since the announcement of its lunar contest, the X Prize Foundation has received extensive public feedback concerning space-heritage sites, and the competing teams discussed the topic at an international meeting in May. Will Pomerantz, the foundation’s director of space projects, says the discussions have indicated a generation gap in public perceptions of the issue.

“Generally speaking, people who were alive to witness the Apollo missions have said we shouldn’t be going anywhere near these sites and they should effectively be put under glass,” Pomerantz says. “The people who were not alive then say just the opposite, that if someone visits one of these sites, it’s a good thing, because it means we’re back on the Moon!” Pomerantz recognizes the wide spectrum of ideas on how to treat these sites, but says the X Prize Foundation should be “the body that makes sure this is done respectfully, rather than the body defining what ‘respectfully’ is.”

Not everyone from the Apollo era is convinced the sites should be off-limits. As part of his Apollo 11 moonwalk, Buzz Aldrin deployed a solar-powered seismometer near the spacecraft. “The seismometer experimenter told me, ‘After you deploy the solar panels in the sunlight, don’t walk in front of them, or you might interrupt the flow of electricity and damage things,’” Aldrin recalls. “Well, if you look very carefully in front of those panels, you’ll see some footprints there. I guess I wouldn’t mind too much if somebody went up there to brush those away.”